The present invention relates to arrangements for filling containers with liquids in general, and more particularly to a discharge nozzle of a container filling valve.
In the known filling machines which are equipped with filling elements which do not contain a filling tube, the liquid flows, after the opening of a liquid flow interrupting valve, along a guiding tube on which there is mounted a flow-deflecting shield which deflects the flow of the liquid away from the guiding tube and toward the inner surface of the circumferential wall of the container being filled with the liquid. The volume of gas which is displaced by the liquid is removed from the container being filled through a gas tube. The rising upper level of the liquid in the container will eventually interrupt the access of the gas to the gas tube, and further flow of the liquid into the container is thus terminated.
Consequently, the gas tube simultaneously performs the function of the filling volume limiter. The gas remaining in the filled container has a tendency, so long as the filling valve is still open, to escape through the column of liquid present upwardly thereof in the upward direction. If this were permitted to happen, the same volume of liquid as that of the escaping gas would flow into the container, so that the liquid contents thereof would be greater than desired. For this reason, a gas trap is ordinarily interposed at a suitable location between the liquid flow interrupting valve and the deflecting shield. The gas trap may be constructed, for instance, as a wire mesh screen. The mesh aperture size of this wire mesh screen is so selected that the surface tension force of the liquid present upwardly of the wire mesh screen between the individual wires exceeds the upwardly directed buoyancy force of the gas. While this wire mesh screen achieves excellent results when the liquid being filled into the container is clear, in that it lets such liquid pass therethrough without any hindrance, it fails when the liquid to be filled into the container carries solid matter, as is the case, for instance, with fruit juices or similar beverages containing fruit or vegetable fibers or tissue. If it were attempted to use the wire mesh screen in conjunction with such liquids, the fibers or similar solid ingredients would soon clog the apertures of the wire mesh screen. This means that filling elements of a different construction must be used for filling containers with liquids of this type.
One construction which has been found to give excellent results under these circumstances includes a filling or liquid discharge valve which includes a siphon-type trap. A valve of this construction usually includes, immediately upwardly of its discharge tube and also upwardly and upstream of its valve seat with an annular depression or groove, into which there extends an also annularly configurated inner tube. When the valve is constructed in this manner, the liquid will be able to flow between the external valve housing and the internal tube into the siphon-type trap, and through the latter into the discharge tube, while the gas remaining in the container will not be able to flow through the siphon-type trap in the opposite direction, even if the valve member of this valve is still spaced from the valve seat.
This construction of the discharge or filling valve is suited for use with many types of liquids, that is, not only with those which contain solid ingredients, but also with those which are clear. However, this construction also has a quite disturbing drawback, which results from the provision of the siphon-type fluid-flow diversion caused by the provision of the necessary web or inner tube at the region of the annular groove. This results in the formation of turbulent flow conditions in the flow of the liquid toward the container being filled which, in turn, decreases the throughput of the filling valve and, consequently, increases the time which is needed for filling the container.